1. Field of the Invention
The invention concerns a method and system for efficiently interfacing marine and rail cargo loading and discharging. More specifically, the invention concerns the integrated simultaneous load and discharge of a container ship and a stack train.
2. Description of the Related Art
Traditionally, general cargo for ships has been assembled at the port of loading prior to the arrival of the vessel. Cargo was either accumulated along the side of the vessel, or was stored in warehouses. This was done to ensure that cargo with the proper attributes was immediately available to load the vessel to prevent or minimize any delay to the vessel. Delay to the vessel is arguably the most expensive component of a cargo transportation system.
Cargo discharged from the vessel was also held in the port area adjacent to the vessel, until arrangements for delivery or on-carriage could be made.
The cargo which is accumulated must take into consideration several points. That is, each ship must be loaded and discharged observing a precise protocol. Cargo must be loaded so as to be forwarded to the correct port. Moreover, a vessel must be loaded and weighted properly, and cargo stored in the proper locations. For example, flammable cargo has special requirements. Therefore, vessel stability, port of discharge, special cargo requirements such as temperature control, dangerous and hazardous material regulations, shipper's special requirements and other considerations must all be met.
Prior to the development of the containerized shipping system, the cargo was simply held on the pier or in the warehouse adjacent to the pier.
Containerized shipping was a large improvement over previous systems. When container ships were small, traditional methods still worked.
However, as ship capacity grew, the warehouses or sheds disappeared and the containers were marshalled in large parking lots near the pier waiting for the ship's arrival. In the case of inbound cargo, the containers in the parking lots were waiting for delivery or on-carriage arrangements to be accomplished.
Parking lots are cheaper and easier to develop than covered sheds. Initially, this was considered to be one of the great benefits to be obtained from the containerized shipping system.
However, as the capacity of the typical container ship increased from about 400 twenty ft. equivalent units (TEU's) to over 4,000 TEU's in the span of 30 years, the size of the area required to accommodate storage of the containers dramatically increased. Whereas 25 acres was once adequate capacity for a shipping terminal, shipping terminals in excess of 200 acres are now under construction.
The disadvantage of these large terminals is that land available in port areas is scarce and very expensive. In addition to the scarcity and expense of the resources, the ability to develop available land has become suspect. Environmental concerns virtually preclude significant reclamation from wetlands in the future, thus threatening the ability to develop the available port area land for adequate storage capacity.
Exacerbating the problem is the fact that existing facilities are nearly at capacity. In spite of this, international container ship traffic is expected to double again in the next 10 years.
There have been many attempts to solve this problem. Typically, these attempts envision a scheme for the vertical stacking of the containers, to make more efficient use of available marine terminal land. In these schemes, large parking lots at the point of discharge are still required, in order to assemble the appropriate inventory of containers, so that a sufficient selection of containers with the desirable attributes are available to ensure a proper stow to the vehicle. Generally, containers just discharged from the vessel must be held in this location until arrangements can be made for delivery or on-carriage.
Thus, while the focus of these systems remains the water front property, there remain certain inefficiencies in loading and discharging vessels.
These more traditional methods and devices for use therewith are shown, for example in U.S. Pat. No. 3,631,993, which discloses a containerized cargo storage and handling system. It includes a storage facility for temporarily storing containers which are being exchanged between a ship and trucks and trains. U.S. Pat. Nos. 3,700,128 and 3,952,891 disclose intermodal transfer systems for exchanging goods between ships and land or air vehicles. U.S. Pat. No. 4,973,219 discloses a high density container storage yard used in exchanging goods between transport ships and rail cars. U.S. Pat. Nos. 4,090,620, 4,293,077 and 4,872,798 all disclose varieties of transfer apparatus for directly conducting goods between ships and rail vehicles.
All of the above fail to solve the problem experienced in existing facilities. Moreover, none of the traditional methods and devices discussed above suggest a way to provide adequate storage capacity, while at the same time making the assembly of cargo for vessels with the required characteristics more efficient.
Thus, there remains a need for a method to efficiently utilize existing limited land in port areas. Moreover, there is an unmet need for a more efficient method to load and discharge container ships while observing the relevant requirements.